1. Field of Endeavor
The present invention relates to shape memory system and more particularly to a shape memory system using a shape memory material with integrated actuation using embedded particles.
2. State of Technology
U.S. Pat. No. 5,895,398 to Jeffrey P. Wensel and Y. Pierre Gobin for a method of using a clot capture coil, issued Apr. 20, 1999, provides the following state of technology information, “A clot and foreign body removal device is described which comprises a catheter with at least one lumen. Located within the catheter is a clot capture coil that is connected to an insertion mandrel. In one embodiment, the clot capture coil is made out of a solid elastic or superelastic material which has shape memory, preferably nitinol. The elasticity or superelasticity of the coil allows it to be deformed within the catheter and to then reform its original coil configuration when the coil is moved outside of the catheter lumen. In another embodiment the coil is a biphasic coil which changes shape upon heating or passing an electric current. Once the coil configuration has been established, the coil can be used to ensnare and corkscrew a clot in a vessel. A clot is extracted from the vessel by moving the clot capture coil and catheter proximally until the clot can be removed or released into a different vessel that does not perfuse a critical organ. Foreign bodies are similarly captured by deploying the coil distal to the foreign body and moving the clot capture coil proximally until the foreign body is trapped within the coil. By removing the device from the body, the foreign material is also removed.” (Abstract)
U.S. Pat. No. 5,911,737 to Abraham P. Lee, M. Allen Northrup, Dino R. Ciarlo, Peter A. Krulevitch, and William J. Benett for microfabricated therapeutic actuators, issued Jun. 15, 1999 provides the following state of technology information, “Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.” (Abstract)
U.S. Pat. No. 6,059,815 to Abraham P. Lee, Joseph P. Fitch, Daniel L. Schumann, Luiz Da Silva, William J. Benett, and Peter A. Krulevitch, issued May 9, 2000, provides the following state of technology information, “Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a retaining/release actuator for the delivery of material, such as embolic coils, for example, through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. The SMP microtubing can be positioned around or within an end of a deposit material. Various heating arrangements can be utilized with the SMP release mechanism, and the SMP microtubing can include a metallic coating for enhanced light absorption.” (Abstract)
U.S. Pat. No. 6,102,917 to Duncan J. Maitland, Abraham P. Lee, Daniel L. Schumann, and Luiz Da Silva, issued Aug. 15, 2000, provides the following state of technology information, “A system for releasing a target material, such as an embolic coil from an SMP located at the end of a catheter utilizing an optical arrangement for releasing the material. The system includes a laser, laser driver, display panel, photodetector, fiber optics coupler, fiber optics and connectors, a catheter, and an SMP-based gripper, and includes a release sensing and feedback arrangement. The SMP-based gripper is heated via laser light through an optic fiber causing the gripper to release a target material (e.g., embolic coil for therapeutic treatment of aneurysms). Various embodiments are provided for coupling the laser light into the SMP, which includes specific positioning of the coils, removal of the fiber cladding adjacent the coil a metal coating on the SMP, doping the SMP with a gradient absorbing dye, tapering the fiber optic end, coating the SMP with low refractive index material and locating an insert between the fiber optic and the coil.” (Abstract)
United States Patent Application No. 2002/0095169 by Duncan J. Maitland, Abraham P. Lee, Daniel L. Schumann, Dennis L. Matthews, Derek E. Decker, and Charles A. Jungreis for a shape memory polymer actuator and catheter provides the following state of technology information, “An actuator system is provided for acting upon a material in a vessel. The system includes an optical fiber and a shape memory polymer material operatively connected to the optical fiber. The shape memory polymer material is adapted to move from a first shape for moving through said vessel to a second shape where it can act upon said material.” (Abstract)
United States Patent Application No. 2003/0236533 by Thomas S. Wilson, Duncan Maitland, Daniel L. Schumann, Steve L. Little, and Paul E. Ahre for a Shape Memory Polymer Actuator and Catheter provides the following state of technology information, “A system for removing an occlusion from a vessel. The system utilizes a shape memory polymer device for acting upon the occlusion. A transport vehicle moves a shape memory material through the vessel. The shape memory material is adapted to move from a first unexpanded coil shape to move through or around the occlusion, to a second expanded coil shape for acting upon the occlusion. A heat transfer mechanism is operatively connected to the shape memory material and is adapted to transfer heat to the shape memory material to move the shape memory material from the first shape to the second shape. The transport vehicle and the shape memory polymer material are withdrawn through the conduit carrying the occlusion matter. The system may include a second shape memory polymer device situated so that the occlusion material is gripped from both sides to facilitate removal.” (Abstract)